The present invention relates to a sputtering apparatus for coating a film of a metal, hard substance and the like upon an article such as cutting tool, wear-resistant piece, and the like.
Conventionally, in order to improve characteristics of cutting tools and wear resistant members such as a bearing, a coating or film of a metal, hard substance and the like has been formed on them by means of an ion-plating process and a physical vapor deposition process such as an activated reactive deposition process.
In one conventional sputtering method, a target is disposed within a vacuum chamber, and an article or substrate to be treated is placed below the target within the vacuum chamber. The target material is vapor deposited on a surface of the article in a well known manner. A bias sputtering method is also known in the art by which a deposited coating of a higher density is formed on an article. A magnetron sputtering method is also known in which a magnetron target of either a cylindrical or a planar type is used. With this method, the deposition speed is increased. However, in the case where cross-sectionally square throw-away tips of cemented carbide (size: 7 mm width.times.7 mm length.times.3 mm thickness to 20 mm width.times.20 mm length.times.200 mm thickness) which require a coating of uniform thickness on eight apexes thereof, drills, hob cutter of high speed steel (200 mm diameter.times.200 mm length), and wear-resistant members of various shapes such as a bearing and a roll are coated with a coating layer of a uniform thickness, using the above conventional sputtering methods, the following disadvantages have been encountered:
(a) The deposited coating exhibits directional properties, and this is marked particularly when the physical vapor deposition method is employed. Therefore, the coating of uniform thickness is not applied to an article or substrate of complicated shape. PA1 (b) When a large number of articles are subjected to deposition coating, the deposition rate and the temperature of the substrate can not be suitably controlled. Therefore, the deposition operation can not be carried out efficiently.